[Arran]

I would get rid of the 80's vintage TV in it for a start, and have a look on the inside for what may have been fitted in there such as mounting blocks or screw holes. Yes, see if you can find any photos of it with the radio inside with the doors open, that will help narrow it down if you want an exact match for what went in there.
I can safely say that it was unlikely that a commercially produced radio ever left the factory in that cabinet, it was custom built. The cabinet may have been made in 1918, though I'm not sure what they would have used it for prior to a radio cabinet, but commercially produced radios were not generally available until 1921-22, and most of those were small sets with three tubes at the most. Big black dials may indicate that it had a TRF radio fitted into it, that would put it in the 1923-26 era, from 1927 onward that they went to single dials and many to peak hole dials. It was quit common for TRF sets of the mid 1920s to have two or more safe style knobs, Atwater Kent and FADA for example, though there were several dozen other makes that used that same layout not to mention home brew and kit sets.
Regards
Arran